Light emitting module

ABSTRACT

A light-emitting module is disclosed. The light-emitting module includes a condensing lens for condensing incident light into a space, a light source for providing first light to pass through the condensing lens, a first optical path conversion member for reflecting the first light to provide first reflected light to pass through the condensing lens, a second optical path conversion member for reflecting the first reflected light to provide second reflected light to pass through the condensing lens and a wavelength conversion unit for receiving the second reflected light, converting a wavelength of the received second reflected light, and radiating light the wavelength of which has been converted.

CLAIM OF PRIORITY

This application is a continuation of U.S. application Ser. No.15/136,241, filed on Apr. 22, 2016, which claims priority to KoreanPatent Application Serial No. 10-2015-0057463, filed on Apr. 23, 2015,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a light-emitting module and a lampdevice for vehicles including the same.

2. Description of the Related Art

In general, vehicles are equipped with lamp devices for illuminatingnearby objects during poor lighting conditions or signaling the state ofdriving to nearby vehicles or pedestrians.

The lamp device for a vehicle includes a head lamp mounted to the frontside of the vehicle and a tail lamp mounted to the rear side of thevehicle. The head lamp is a lamp for illuminating the area ahead whiledriving at night. The tail lamp includes a brake lamp, which is turnedon when a driver steps on a brake, and a turn signal lamp, whichindicates the direction of travel of the vehicle.

Recently, light-emitting diodes or laser diodes have been used as lightsources for automotive lamp devices for good energy efficiency.

In particular, laser diodes are receiving attention due to their highdegree of straightness, long-distance illumination and non-disturbanceof the field of vision of drivers of oncoming vehicles.

The laser diode needs a phosphor and a lens assembly in order to outputwhite light. However, this complicates the structure of the automotivelamp device, reduces efficiency, and increases the volume of the device.The lamp device for vehicles having a conventional laser diode will nowbe described.

FIG. 19 is a conceptual view of a conventional light-emitting module.Referring to FIG. 19, a conventional light-emitting module operates insuch a manner that blue light generated from a laser diode is focusedwhile passing through a prism 3 and a lens 4, the focused light isreflected from a first reflection unit 5, passes through a lighttransmissive phosphor 6 and is converted into white light, and the whitelight is radiated forward from a second reflection unit 7.

However, if the light-emitting module is arranged lengthwise along anoptical axis inside the head lamp for vehicles, the length of the headlamp may be increased.

Further, since the conventional light-emitting module needs a relativelylarge number of components and has an optical path structure in whichthe light passes through each component only once, it may be hard tomanufacture a compact head lamp due to the overall size of thecomponents.

In addition, using a large number of components may increase costs anddeteriorate reliability, and using the light transmissive phosphor maycause a decrease in efficiency.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the aboveproblems, and it is an object of the present invention to provide alight-emitting module which has good efficiency, light convergence andstraightness and is reduced in size.

In accordance with an aspect of the present invention, the above andother objects can be accomplished by the provision of a light-emittingmodule including a condensing lens for condensing incident light into aspace, a light source for providing first light to pass through thecondensing lens, a first optical path conversion member for reflectingthe first light to provide first reflected light to pass through thecondensing lens, a second optical path conversion member for reflectingthe first reflected light to provide second reflected light to passthrough the condensing lens and a wavelength conversion unit forreceiving the second reflected light, converting a wavelength of thereceived second reflected light, and radiating light the wavelength ofwhich has been converted.

The light-emitting module may further include an auxiliary condensinglens for concentrating the second reflected light having passed throughthe condensing lens on a predetermined spot in the front.

The light source and the second reflection unit may be locatedeccentrically from a central axis of the condensing lens.

The light source and the second reflection unit may be located oppositeeach other across the central axis of the condensing lens.

The light source may be spaced apart from the central axis of thecondensing lens in a first direction which is perpendicular to thecentral axis of the condensing lens, and the second reflection unit maybe spaced apart from the central axis of the condensing lens in a seconddirection which is opposite to the first direction.

The first reflection unit may be spaced apart from the central axis ofthe condensing lens in the first direction.

A first distance between the central axis of the condensing lens and thelight source may be smaller than a radius of the condensing lens.

A second distance between the central axis of the condensing lens andthe second reflection unit may be smaller than the radius of thecondensing lens.

A third distance between the central axis of the condensing lens and thefirst reflection unit may be smaller than the radius of the condensinglens.

The second reflection unit may convert the first reflected lightincident thereon into second reflected light having a wavelengthdifferent from that of the first reflected light.

A spot of incidence of a front surface of the condensing lens, on whichthe first reflected light is incident, may be located apart from thecentral axis of the condensing lens in the second direction.

A fourth distance between the central axis of the condensing lens andthe spot of incidence may be smaller than the first distance or thesecond distance.

A ratio of the first distance to the second distance may be in the rangeof 1:0.7 to 1:1.1.

A ratio of the first distance to the fourth distance may be in the rangeof 1:0.1 to 1:0.6.

The condensing lens may be divided into a first region and a secondregion by an imaginary section cut along the central axis of thecondensing lens, the first light may be incident on the first region,the first reflected light may be incident on the second region, and thesecond reflected light may be incident on the second region.

The first light may be incident parallel to the central axis of thecondensing lens. The condensing lens may be a non-spherical lens.

The non-spherical lens may include a rear surface which is perpendicularto the central axis of the condensing lens, and a front surface which isformed to be convex in the front direction of the condensing lens.

The second reflection unit may include a wavelength conversion layer forconverting a wavelength of incident light, and a reflection layer forreflecting the incident light.

The light source may include a laser diode.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a conceptual view of a light-emitting module according to anembodiment of the present invention;

FIG. 2 is a conceptual view illustrating the optical path of alight-emitting module according to an embodiment of the presentinvention;

FIGS. 3 and 4 are reference views for explaining refraction andreflection of a light-emitting module according to an embodiment of thepresent invention;

FIG. 5A is a sectional view of a wavelength conversion unit according toan embodiment of the present invention;

FIG. 5B is a plan view of a wavelength conversion unit according to anembodiment of the present invention when viewed from the front of anoptical axis;

FIG. 6A is a conceptual view of a light-emitting module according toanother embodiment of the present invention;

FIG. 6B is a conceptual view of a light-emitting module according to afurther embodiment of the present invention;

FIGS. 7A and 7B are views illustrating an optical path and a projectionimage of a light-emitting module according to the present invention;

FIG. 8 is a conceptual view of a light-emitting module according toanother embodiment of the present invention;

FIGS. 9A and 9B are conceptual views of a light emitting moduleaccording to another embodiment of the present invention when viewed indifferent directions;

FIG. 10 is a conceptual view illustrating an optical path of the lightemitting module according to the embodiment of the present invention;

FIG. 11 is a reference view for explaining the position of the lightemitting module according to the embodiment of the present invention;

FIG. 12A is a sectional view of a condensing lens taken along line I-Iof FIG. 9A;

FIG. 12B is a sectional view of the condensing lens taken along lineII-II of FIG. 9B;

FIG. 13A is a sectional view of a condensing lens and a first opticalpath conversion member according to another embodiment of the presentinvention;

FIG. 13B is a sectional view of a condensing lens and a first opticalpath conversion member according to another embodiment of the presentinvention;

FIG. 13C is a sectional view of a condensing lens and a first opticalpath conversion member according to another embodiment of the presentinvention;

FIG. 13D is a sectional view of a condensing lens and a first opticalpath conversion member according to a further embodiment of the presentinvention;

FIG. 14A is a longitudinal sectional view cut through an auxiliarycondensing lens according to an embodiment of the present invention inthe vertical direction;

FIG. 14B is a cross sectional view cut through the auxiliary condensinglens according to the embodiment of the present invention in thehorizontal direction;

FIG. 15A is a conceptual view of a light emitting module according toanother embodiment of the present invention;

FIG. 15B is a conceptual view of a light emitting module according toanother embodiment of the present invention;

FIG. 15C is a conceptual view of a light emitting module according toanother embodiment of the present invention;

FIG. 15D is a conceptual view of a light emitting module according to afurther embodiment of the present invention; and

FIG. 16 is a view illustrating an optical path of the light emittingmodule according to the present invention.

FIG. 17 is a view illustrating a car equipped with a light-emittingmodule according to the present invention;

FIG. 18 is a sectional view illustrating a lamp device for vehiclesincluding a light-emitting module according to the present invention;and

FIG. 19 is a conceptual view of a conventional light-emitting module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

Referring to FIGS. 1 and 2, a light-emitting module 10 according to anembodiment of the present invention comprises a condensing lens 30 forconcentrating light incident thereinto on a predetermined spot, a lightsource 20 disposed behind the condensing lens 30 to emit first light 21toward the condensing lens 30, a first optical path conversion unit 40disposed in front of the condensing lens 30 to reflect the first light21, having passed through the condensing lens 30, and supply firstreflected light 22 to the condensing lens 30, a second optical pathconversion unit 50 disposed behind the condensing lens 30 to reflect thefirst reflected light 22, having passed through the condensing lens 30,and supply second reflected light 23 to the condensing lens 30, and awavelength conversion unit 70 for converting the second reflected light23, incident thereinto, into light having a different wavelength fromthat of the second reflected light 23 and emitting the light.

Here, the direction “front” refers to the right side (direction of −Ax1)along a central axis Ax1 and −Ax1 (also referred to as an optical axis)of the condensing lens 30 in FIG. 1. The direction “rear” refers to theleft side (direction of −Ax1) along the central axis Ax1 and −Ax1 of thecondensing lens 30 in FIG. 1.

The central axis Ax1 of the condensing lens 30 is an imaginary linewhich connects the focal point of a front surface 31 of the condensinglens 30 with the center of the condensing lens 30.

The condensing lens 30 functions to concentrate light incident from therear of the optical axis on a predetermined spot in the front of theoptical axis. The condensing lens 30 refracts the incident light due tothe shape of the condensing lens 30 and the difference in refractiveindex between the condensing lens 30 and the outside. The refractiveindex of the condensing lens 30 may be greater than 1, and preferably,may range from 1.5 to 1.6.

For example, the condensing lens 30 includes a spherical lens or anon-spherical lens. Preferably, the condensing lens 30 may be embodiedas a non-spherical lens.

The condensing lens 30 may have a shape that is convex in the frontdirection of the optical axis Ax. In another example, the condensinglens 30 may include a rear surface 32 which is perpendicular to thecentral axis Ax1 of the condensing lens 30, and a front surface 31 whichis formed to be convex in the front direction of the condensing lens 30.Alternatively, the rear surface 32 may be formed to be concave in thefront direction of the optical axis.

The front surface 31 of the condensing lens 30 is formed in a curveshape having a peak which lies on the central axis Ax1 of the condensinglens 30. In detail, the front surface 31 of the condensing lens 30 maybe formed in a curve shape which has a focal point on the central axisAx1 of the condensing lens 30 and multiple radii of curvature.

The condensing lens 30 refracts light that is incident parallel to thecentral axis Ax1 of the condensing lens 30, and concentrates the lighton a predetermined spot in the front region of the optical axis. Thecondensing lens 30 may be made of various materials that light canpenetrate.

The light source 20 functions to generate light by receiving electricalenergy and converting the electrical energy into optical energy. Forexample, the light source 20 may be embodied as an ultra-high voltage(UHV) mercury lamp, a light-emitting diode (LED), a laser diode (LD) orthe like. Preferably, the light source 20 may be embodied as a laserdiode having good light straightness and convergence.

Various power supplies may supply power to the light source 20. Thepower may be supplied by a printed circuit board (PCB), a metal corePCB, a flexible PCB, a ceramic PCB or the like.

Here, the laser diode is a semiconductor laser having two electrodes forperforming laser processes. For example, the laser diode may have aGaAs, Al_(x)Ga_(1-x)As double heterojunction structure.

The light source 20 may generate various colors of light. Preferably,the light source 20 generates blue-based light having good efficiency.

The light source 20 is disposed behind the condensing lens 30, and emitsthe first light 21 toward the condensing lens 30. The first light 21 isincident parallel to the central axis Ax1 (optical axis) of thecondensing lens 30. Here, the term “parallel” does not refer to aparallel state in the mathematical sense, but refers to a substantiallyparallel state within the allowable range.

The first light 21 is incident into the condensing lens 30 through apoint on the rear surface 32 of the condensing lens 30 that is locatedeccentrically from the central axis Ax1 of the condensing lens 30.

In detail, the condensing lens 30 may be divided into a first region anda second region by an imaginary section cut along the central axis Ax1of the condensing lens 30.

For example, as shown in FIG. 1, the first region is an upper region(region in the direction of Z-axis) above the central axis Ax1 of thecondensing lens 30. The second region is a lower region (region in thedirection of −Z-axis) below the central axis Ax1 of the condensing lens30. In this situation, the first light 21 is incident into the firstregion of the condensing lens 30.

To achieve this, the light source 20 is located eccentrically from thecentral axis Ax1 of the condensing lens 30. The light source 20 isspaced apart from the central axis Ax1 of the condensing lens 30 in afirst direction (direction of Z-axis) which is perpendicular to thecentral axis Ax1 of the condensing lens 30. The light source 20 and thesecond reflection unit 50 are located opposite each other across thecentral axis Ax1 of the condensing lens 30.

The first light 21 generated from the light source 20 is incident on apoint that is eccentric from the central axis Ax1 of the condensing lens30, is refracted from the front surface 31 of the condensing lens 30,and is then incident on the first reflection unit 40.

The first reflection unit 40 is disposed in front of the condensing lens30, reflects the first light 21 having passed through the condensinglens 30, and supplies the first reflected light 22 to the condensinglens 30.

In detail, the first reflection unit 40 is arranged so that the firstreflected light 22 can pass through the condensing lens 30 from thefront surface 31 to the rear surface 32 thereof. The first reflectionunit 40 may include a planar surface or a curved surface. According tothe number of light sources 20, a plurality of first reflection units 40may be arranged in a stair shape. Further, the first reflection unit 40may be rotatably structured so as to adjust the angle of the firstreflected light 22.

In greater detail, in order to effectively arrange the components in thelimited space of the lamp device for vehicles and increase theefficiency thereof, the first reflection unit 40 is arranged so that thefirst reflected light 22 is incident into the condensing lens 30 througha point on the front surface 31 of the condensing lens 30 that islocated eccentrically from the central axis Ax1 of the condensing lens30. At this time, it is preferable that the first reflected light 22 isincident into the second area of the condensing lens 30.

The spot of incidence of the front surface 31 of the condensing lens 30,on which the first reflected light 22 is incident, is located apart fromthe central axis Ax1 of the condensing lens 30 in a second direction. Inother words, the first reflected light 22 is incident into anotherregion of the condensing lens 30, which is symmetrical to the region ofthe condensing lens 30 into which the first light 21 is incident.

If the first reflection unit 40 is disposed on the central axis Ax1 ofthe condensing lens 30, it has a shortcoming in that the distancebetween the first reflection unit 40 and the light source is increased,and thus the overall length of the light-emitting module 10 isincreased. Therefore, it is preferable that the first reflection unit 40is disposed at a position spaced apart from the central axis Ax1 of thecondensing lens 30 in the first direction (direction of Z-axis) which isperpendicular to the central axis Ax1 of the condensing lens 30.

For example, the first reflection unit 40 includes a reflection layerwhich has a reflection surface intersecting the optical axis. Here, thereflection layer may be made from a material having a good reflectionproperty, for example, a material selected from the group consisting ofAg, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf and a combinationthereof.

The reflection layer may have a structure in which a plurality of layershaving different refractive indexes are alternately stacked.

The second reflection unit 50 is disposed behind the condensing lens 30,reflects the first reflected light 22 having passed through thecondensing lens 30, and supplies the second reflected light 23 to thecondensing lens 30.

The second reflection unit 50 may function only to reflect the light, orto convert a wavelength of the light while reflecting the light. Forexample, the second reflection unit 50 may convert the wavelength of theblue-based light emitted from the light source 20 and generatewhite-based light. The detailed structure of the second reflection unit50 will be described later. According to the purpose of thelight-emitting module 10, the second reflection unit 50 may bestructured only to reflect the light, or to convert the wavelength ofthe light during the reflection. Accordingly, the second reflected light23 reflected from the second reflection unit 50 may have a wavelengththat is different from that of the first reflected light 22.

The second reflection unit 50 is disposed behind the condensing lens 30,and supplies the second reflected light 23 to the condensing lens 30.

The first reflected light 22, which is incident on the front surface 31of the condensing lens 30 from the first reflection unit 40, isrefracted at the boundary surfaces of the condensing lens 30, and isradiated from the rear surface 32 of the second region of the condensinglens 30. The first reflected light 22, having passed through thecondensing lens 30, is incident on the second reflection unit 50, and isreflected as the second reflected light 23 from the second reflectionunit 50. The second reflected light 23 is incident on a region of therear surface 32 that is eccentric from the central axis Ax1 of thecondensing lens 30. In detail, the second reflected light 23 is incidenton the second region of the rear surface 32 of the condensing lens 30.

The reflection property of light will now be described.

Light may be specularly reflected or diffusely reflected based on thesurface property of the reflector.

Diffuse reflection may include Gaussian reflection, Lambertianreflection and mixed reflection.

In general, specular reflection is reflection in which, when light isincident on a point of the reflector, an angle between a normal linepassing the point and an optical axis of the incident light is equal toan angle between the normal line and an optical axis of reflected light.

Gaussian reflection is reflection in which intensity of reflected lightbased on an angle at the surface of the reflector and an angle between anormal line and the reflected light vary according to values of aGaussian function.

Lambertian reflection is reflection in which intensity of reflectedlight based on an angle at the surface of the reflector and an anglebetween a normal line and the reflected light vary according to valuesof a cosine function.

The mixed reflection includes at least one selected from among specularreflection, Gaussian reflection and Lambertian reflection.

In one embodiment, the first reflection unit 40 specularly reflectslight for light focusing. In the case in which the second reflectionunit 50 functions only to reflect light, the second reflection unit 50specularly reflects light.

In another embodiment, in the case in which the second reflection unit50 is configured to perform both reflection and wavelength conversion,the second reflection unit 50 has a structure including a reflectionlayer and a phosphor layer coated on the reflection layer. When thesecond reflection unit 50 performs reflection and wavelength conversion,the second reflected light 23 from the second reflection unit 50undergoes Lambertian reflection or mixed reflection. Accordingly, whenthe second reflection unit 50 performs reflection and wavelengthconversion, the second reflected light 23 is radiated ahead of theoptical axis Ax. In other words, the second reflected light 23 becomesfan-shaped light which is directed at a predetermined angle in upper andlower directions based on an arbitrary line parallel to the central axisAx1 of the condensing lens 30.

Preferably, the reflection surface of the second reflection unit 50 isarranged perpendicular to the central axis Ax1 of the condensing lens30.

The second reflected light 23 is incident on the second region of therear surface 32 of the condensing lens 30, is refracted at the boundarysurfaces of the condensing lens 30, and is radiated from the condensinglens 30. The second reflected light 23 having passed through thecondensing lens 30 has a smaller radiation angle than the secondreflected light 23 that is incident into the condensing lens 30.

Accordingly, the second reflected light 23 having passed through thecondensing lens 30 is diffused while having a certain degree ofstraightness. Such second reflected light 23 may be used as a low beamin a lamp device for vehicles, which illuminates a region spaced apartby a short distance.

The second reflection unit 50 is disposed at a position spaced apartfrom the central axis Ax1 of the condensing lens 30 in the seconddirection (direction of −Z-axis) which is perpendicular to the centralaxis Ax1 of the condensing lens 30. The second reflection unit 50 islocated opposite the light source 20 across the central axis Ax1 of thecondensing lens 30.

In a further embodiment, the second reflected light 23 may be convertedinto light that is substantially parallel to the optical axis so as tobe used as a high beam for illuminating a region spaced apart by a longdistance. In this case, the light-emitting module according to thisembodiment may further comprise an auxiliary condensing lens 60 forconcentrating the second reflected light 23 having passed through thecondensing lens 30 on a predetermined spot in the front.

The auxiliary condensing lens 60 functions to concentrate light incidentfrom the rear of the optical axis on a predetermined spot in the frontof the optical axis. The auxiliary condensing lens 60 refracts theincident light due to the shape of the auxiliary condensing lens 60 andthe difference in refractive index between the auxiliary condensing lens60 and the outside. The refractive index of the auxiliary condensinglens 60 may be greater than 1, and preferably, may range from 1.5 to1.6.

For example, the auxiliary condensing lens 60 includes a spherical lensor a non-spherical lens. Preferably, the auxiliary condensing lens 60may be embodied as a non-spherical lens.

The auxiliary condensing lens 60 may have a shape that is convex in thefront direction of the optical axis Ax1. In another example, theauxiliary condensing lens 60 may include a rear surface which isperpendicular to a central axis Ax2 of the auxiliary condensing lens 60,and a front surface which is formed to be convex in the front directionof the auxiliary condensing lens 60. Alternatively, the rear surface maybe formed to be concave in the front direction of the optical axis.

The central axis Ax2 of the auxiliary condensing lens 60 is eccentricfrom the central axis Ax1 of the condensing lens 30. In detail, thecentral axis Ax2 of the auxiliary condensing lens 60 may be locatedwithin the second region of the condensing lens 30. Preferably, thecentral axis Ax2 of the auxiliary condensing lens 60 is parallel to thecentral axis Ax1 of the condensing lens 30.

The light incident into the auxiliary condensing lens 60 from the rearis refracted at the boundary surfaces of the auxiliary condensing lens30, and is radiated as light parallel to the optical axis.

The wavelength conversion unit 70 functions to convert the wavelength ofthe second reflected light 23 incident thereinto. For example, thewavelength conversion unit 70 may convert the wavelength of theblue-based light emitted from the light source 20 and generatewhite-based light.

The wavelength conversion unit 70 may include a well-known phosphor forconverting the wavelength of light. The detailed structure of thewavelength conversion unit 70 will be described later.

After passing through the wavelength conversion unit 70, the secondreflected light 23 is incident into the condensing lens 30 or/and theauxiliary condensing lens 60. In an example, as shown in FIG. 1, thewavelength conversion unit 70 is disposed between the condensing lens 30and the second optical path conversion unit 50. The wavelengthconversion unit 70 receives the second reflected light 23, radiated fromthe second optical path conversion unit 50, and supplies the secondreflected light 23 to the second region of the condensing lens 30.

In particular, the wavelength conversion unit 70 is decentered withrespect to the central axis Ax1 of the condensing lens 30, and islocated opposite to the light source 20. The wavelength conversion unit70 is located near the second region.

The second reflected light 23 from the wavelength conversion unit 70 isradiated in the forward direction of the optical axis Ax. In otherwords, the second reflected light 23, radiated from the wavelengthconversion unit 70, becomes fan-shaped light, which is directed at apredetermined angle in upper and lower directions with respect to anarbitrary line parallel to the central axis Ax1 of the condensing lens30.

Preferably, the reflecting surface of the second optical path conversionunit 50 is arranged to cross or to be perpendicular to the central axisAx1 of the condensing lens 30.

The second reflected light 23 is incident on the second region of therear surface 32 of the condensing lens 30, is refracted at the boundarysurfaces of the condensing lens 30, and is radiated from the condensinglens 30. The second reflected light 23 that has passed through thecondensing lens 30 has a smaller angle of radiation than the secondreflected light 23 that is incident into the condensing lens 30.

Accordingly, the second reflected light 23 that has passed through thecondensing lens 30 is diffused while having a certain degree ofstraightness. Such second reflected light 23 may be used as a low beamin a lamp device for vehicles, which illuminates a short-distanceregion.

The second optical path conversion unit 50 is disposed at a positionspaced apart from the central axis Ax1 of the condensing lens 30 in thesecond direction (direction of −Z-axis), which is perpendicular to thecentral axis Ax1 of the condensing lens 30. The second optical pathconversion unit 50 and the light source 20 are located opposite to eachother across the central axis Ax1 of the condensing lens 30.

FIGS. 3 and 4 are reference views for explaining refraction andreflection of the light-emitting module 10 according to an embodiment ofthe present invention.

First, referring to FIG. 4, Snell's law related to light refraction isas follows.

n sin i=n′ sin i′

A refraction formula is deduced by transforming Snell's law as follows.

ni ≅ n^(′)i^(′) n(α − u) = n^(′)(α − u^(′))${n( {\frac{h}{r} - u} )} = {n^{\prime}( {\frac{h}{r} - u^{\prime}} )}$${n^{\prime}u^{\prime}} = {{nu} + {\frac{h}{r}( {n^{\prime} - n} )}}$

Here, n refers to a refractive index of a medium before refraction, n′refers to a refractive index of the medium after refraction, i refers toan angle between a plane onto which light is incident and a verticalplane, and i′ refers to an angle between radiated light and the verticalplane.

Using the above refraction formula, a distance h of each component fromthe central axis Ax1 of the condensing lens 30 can be calculated asfollows.

${n^{\prime}u^{\prime}} = { {{nu} + {\frac{h}{r}( {n^{\prime} - n} )}}\Rightarrow h  = \frac{r( {{n^{\prime}u^{\prime}} - {nu}} )}{( {n^{\prime} - n} )}}$

Here, r refers to a radius of curvature of the lens.

The condensing lens 30 in this embodiment is embodied as a non-sphericallens, in which a radius of curvature of a center portion is smaller thanthat of an edge portion.

When observed from the front of the central axis Ax1 of the condensinglens 30, the light source 20, the first reflection unit 40 and thesecond reflection unit 50 are disposed at positions that overlap thecondensing lens 30. Therefore, the housing accommodating thelight-emitting module 10 may be reduced to the size of the condensinglens 30.

In detail, a first distance h1 between the central axis Ax1 of thecondensing lens 30 and the light source 20 is smaller than a radius L ofthe condensing lens 30. Here, the first distance h1 is calculated usingthe above-mentioned distance calculation formula.

A second distance h2 between the central axis Ax1 of the condensing lens30 and the second reflection unit 50 is smaller than the radius L of thecondensing lens 30. Of course, the second distance h2 is also calculatedusing the above-mentioned distance calculation formula. The secondreflection unit 50 is located behind the condensing lens 30, and moreprecisely, at a position adjacent to the rear surface 32 of thecondensing lens 30.

Preferably, the first distance h1 of the light source 20 and the seconddistance h2 of the second reflection unit 50 may be equal. Morepreferably, a ratio of the first distance h1 to the second distance h2may be in the range of 1:0.7 to 1:1.1. Much more preferably, the ratioof the first distance h1 to the second distance h2 may be in the rangeof 1:0.94 to 1:0.98.

A third distance h3 between the central axis Ax1 of the condensing lens30 and the first reflection unit 40 is greater than 0 and smaller thanthe radius L of the condensing lens 30. Of course, the third distance h3is also calculated using the above-mentioned distance calculationformula.

A fourth distance h4 between the central axis Ax1 of the condensing lens30 and the spot of incidence of the first reflected light 22 may besmaller than the first distance h1 or the second distance h2.Preferably, a ratio of the first distance h1 of the light source 20 tothe fourth distance h4 of the spot of incidence may be in the range of1:0.1 to 1:0.6. More preferably, the ratio of the first distance h1 ofthe light source 20 to the fourth distance h4 of the spot of incidencemay be in the range of 1:0.35 to 1:0.37.

For convenience of assembly, the light-emitting module 10 is generallyaccommodated in a hexahedron-shaped housing. By disposing the lightsource 20 at the upper portion behind the condensing lens 30 anddisposing the second reflection unit 50 at the lower portion behind thecondensing lens 30, the length of the light-emitting module 10 may bereduced, and space utilization may be maximized. As a result, thelight-emitting module 10 may be easily accommodated in the housing.

Further, by disposing the auxiliary condensing lens 60 at the lowerportion in front of the condensing lens 30 and disposing the firstreflection unit 40 at the upper portion in front of the condensing lens30, the length of the light-emitting module 10 may be reduced, and spaceutilization may be maximized, so that the light-emitting module 10 canbe easily accommodated in the housing.

FIG. 5A is a sectional view of the wavelength conversion unit accordingto an embodiment of the present invention, and FIG. 5B is a plan view ofthe wavelength conversion unit according to an embodiment of the presentinvention when viewed from the front of the optical axis.

Referring to FIG. 5B, the wavelength conversion unit 70 may have astructure in which phosphors (not shown) are spread on a base layer,such as transparent silicon or the like. The kind of phosphor may bedetermined based on the wavelength of the light emitted from the lightsource 20 such that the light-emitting module 10 emits white light.

Based on the wavelength of the light emitted from the light source 20,the phosphor may be embodied as one of a blue light-emitting phosphor, ablue-green light-emitting phosphor, a green light-emitting phosphor, ayellow-green light-emitting phosphor, a yellow light-emitting phosphor,a yellow-red light-emitting phosphor, an orange light-emitting phosphor,and a red light-emitting phosphor.

In detail, when the light source 20 is a blue laser diode and thephosphor (not shown) is a yellow phosphor, the yellow phosphor may emityellow light by being excited by blue light, and the blue light from theblue laser diode and the yellow light generated by excitation by theblue light are mixed. As a result, the light-emitting module 10 may emitwhite light.

The wavelength conversion unit 70 includes an incidence surface 70 a, aradiation surface 70 b, and side surfaces 70 c. The incidence surface 70a of the wavelength conversion unit 70 is the surface on which thesecond reflected light 23 is incident. The radiation surface 70 b of thewavelength conversion unit 70 is arranged opposite to the incidencesurface 70 a. The radiation surface 70 b is the surface from which thesecond reflected light 23, which was incident on the incidence surface70 a, is radiated. The side surfaces 70 c are the surfaces that connectthe incidence surface 70 a and the radiation surface 70 b. Each of theside surfaces 70 c has a smaller area than the incidence surface 70 aand the radiation surface 70 b.

The incidence surface 70 a and the radiation surface 70 b of thewavelength conversion unit 70 are arranged so as to cross the centralaxis Ax1 of the condensing lens 30. The wavelength conversion unit 70further includes a heat sink for dissipating heat.

The heat sink is disposed in contact with the side surfaces 70 c of thewavelength conversion unit 70 so as not to block the light passingthrough the wavelength conversion unit 70. The heat sink has a space inwhich the wavelength conversion unit 70 is located, and is arranged tosurround the wavelength conversion unit 70.

FIG. 6A is a conceptual view of a light-emitting module according toanother embodiment of the present invention.

Referring to FIG. 6A, the light-emitting module according to thisembodiment and the light-emitting module according to the embodimentshown in FIG. 1 differ as to the position of the wavelength conversionunit 70.

The wavelength conversion unit 70 in the light-emitting module accordingto another embodiment may be located between the condensing lens 30 andthe auxiliary condensing lens 60. The wavelength conversion unit 70receives the second reflected light 23 from the condensing lens 30 andsupplies the second reflected light 23 to the auxiliary condensing lens60. The second reflected light 23, radiated from the second optical pathconversion unit 50, is incident into the condensing lens 30, and thesecond reflected light 23, radiated from the condensing lens 30, isincident into the wavelength conversion unit 70. The light radiated fromthe wavelength conversion unit 70 is incident into the auxiliarycondensing lens 60.

In particular, the wavelength conversion unit 70 is decentered withrespect to the central axis Ax1 of the condensing lens 30, and islocated opposite to the light source 20. The wavelength conversion unit70 is located near the second region. The wavelength conversion unit 70is located in front of the condensing lens 30.

FIG. 6B is a conceptual view of a light-emitting module according to afurther embodiment of the present invention.

Referring to FIG. 6B, the light-emitting module according to thisembodiment and the light-emitting module according to the embodimentshown in FIG. 1 differ as to the position of the wavelength conversionunit 70.

The wavelength conversion unit 70 in the light-emitting module accordingto a further embodiment may be located on one surface of the condensinglens 30. Particularly, the wavelength conversion unit 70 is coated onthe front surface or the rear surface of the condensing lens 30. Moreparticularly, the wavelength conversion unit 70 is coated on the frontsurface of the condensing lens 30.

The wavelength conversion unit 70 receives the second reflected light 23from the condensing lens 30 and supplies the second reflected light 23to the auxiliary condensing lens 60. The second reflected light 23,radiated from the second optical path conversion unit 50, is incidentinto the condensing lens 30, and the second reflected light 23, radiatedfrom the condensing lens 30, is incident into the wavelength conversionunit 70. The light radiated from the wavelength conversion unit 70 isincident into the auxiliary condensing lens 60.

In particular, the wavelength conversion unit 70 is decentered withrespect to the central axis Ax1 of the condensing lens 30, and islocated opposite to the light source 20. The wavelength conversion unit70 is located near the second region. The wavelength conversion unit 70is located on the front surface of the condensing lens 30.

FIGS. 7A and 7B are views illustrating an optical path and a projectionimage of the light-emitting module 10 according to the presentinvention.

Referring to FIG. 7A, the first light 21 generated from the light source20 is incident into the upper region (first region) of the condensinglens 30, is refracted, and is radiated from the condensing lens 30. Thefirst light 21 radiated from the condensing lens 30 is incident on thefirst reflection unit 40.

The first light 21 incident on the first reflection unit 40 is reflectedtherefrom, and is radiated as the first reflected light 22. The firstreflected light 22 is incident into the lower region (second region) ofthe condensing lens 30. The first reflected light 22 is radiatedrearward through the lower region of the condensing lens 30.

The first reflected light 22 radiated from the condensing lens 30 isincident on the second reflection unit 50. The first reflected light 22is converted into white light at the second reflection unit 50 bywavelength conversion, is reflected from the second reflection unit 50,and is radiated as the second reflected light 23.

At this time, since the second reflected light 23 undergoes Lambertianreflection, the second reflected light 23 becomes fan-shaped light whichis directed at a predetermined angle based on an arbitrary line parallelto the optical axis.

The second reflected light 23 is incident into the lower region of thecondensing lens 30, is refracted, and is radiated ahead of thecondensing lens 30.

The second reflected light 23 radiated from the condensing lens 30 isconcentrated by the auxiliary condensing lens 60, and is radiated as thesecond light 24.

The majority of the second reflected light 23 is incident into theauxiliary condensing lens 60, and is refracted to be parallel light.

From FIG. 7B, illustrating a projection image at 20 meters ahead of thelight source 20, it can be known that the majority of the light isconcentrated on a small region.

FIG. 8 is a conceptual view of a light-emitting module according toanother embodiment of the present invention.

Referring to FIG. 8, the number of light sources 20 in thelight-emitting module 10 according to another embodiment is differentfrom that in the light-emitting module of the previous embodiment, shownin FIG. 1.

FIGS. 9A and 9B are conceptual views of a light emitting moduleaccording to another embodiment of the present invention when viewed indifferent directions, and FIG. 10 is a conceptual view illustrating anoptical path of the light emitting module according to the embodiment ofthe present invention.

Referring to FIGS. 9 and 10, a light emitting module 10 according toanother embodiment of the present invention includes a condensing lens30 for condensing incident light into a space, a light source 20disposed at one side of the condensing lens 30 so as to be spaced apartfrom the condensing lens 30, a first optical path conversion member 40disposed at the other side of the condensing lens 30, a second opticalpath conversion member 50 disposed at one side of the condensing lens 30so as to be spaced apart from the condensing lens 30, the second opticalpath conversion member 50 also being spaced apart from the light source20, and a wavelength conversion unit 70 for converting the wavelength oflight incident from the second optical path conversion member 50 andradiating light the wavelength of which has been converted.

Specifically, the light emitting module 10 includes a condensing lens 30for condensing light incident from the rear into a front space, a lightsource 20 disposed behind the condensing lens 30 for providing firstlight 21 to pass through the condensing lens 30, a first optical pathconversion member 40 disposed in front of the condensing lens 30 forreflecting the first light 21 to provide first reflected light 22 topass through the condensing lens 30, a second optical path conversionmember 50 disposed behind the condensing lens 30 for providing the firstreflected light incident thereon as second reflected light 23 to passthrough the condensing lens 30, and a wavelength conversion unit 70 forreceiving the second reflected light 23, converting the wavelength ofthe received second reflected light 23, and radiating light thewavelength of which has been converted. In addition, the light emittingmodule 10 further includes an auxiliary condensing lens 60 disposed infront of the condensing lens 30 for condensing the second reflectedlight 23 having passed through the condensing lens 30 in the forwarddirection.

The condensing lens 30 condenses light incident from the rear of anoptical axis into a space in front of the optical axis. The condensinglens 30 refracts the incident light due to the shape of the condensinglens 30 and the difference in refractive index between the condensinglens 30 and the outside. The refractive index of the condensing lens 30may be greater than 1. The refractive index of the condensing lens 30may range, for example, from 1.5 to 1.6.

The condensing lens 30 refracts light that is incident parallel to acentral axis Ax1 of the condensing lens 30, and concentrates the lighton an arbitrary spot in front of the optical axis. The condensing lens30 may be made of various materials that light can penetrate.

The light source 20 generates light by receiving electrical energy andconverting the electrical energy into optical energy. For example, thelight source 20 may be embodied as an ultra-high voltage (UHV) mercurylamp, a light emitting diode (LED), a laser diode (LD), or the like.Specifically, the light source 20 may be embodied as a laser diodehaving good light straightness and convergence.

The light source 20 is disposed behind the condensing lens 30 forproviding first light 21 to pass through the condensing lens 30. Thefirst light 21 is incident parallel to the central axis Ax1 (opticalaxis) of the condensing lens 30. Here, the term “parallel” does notrefer to a parallel state in the mathematical sense, but refers to aparallel state within the allowable range.

The first light 21 is incident on the rear surface 32 of the condensinglens 30, which is decentered with respect to the central axis Ax1 of thecondensing lens 30.

More specifically, the condensing lens 30 may be divided into a firstregion and a second region by a section cut along the central axis Ax1of the condensing lens 30.

For example, as shown in FIG. 1, the first region is an upper region (aregion in the direction of Z-axis) above the central axis Ax1 of thecondensing lens 30. The second region is a lower region (a region in thedirection of −Z-axis) below the central axis Ax1 of the condensing lens30. In this situation, the first light 21 is incident on the firstregion of the condensing lens 30.

To this end, the light source 20 is located so as to be decentered withrespect to the central axis Ax1 of the condensing lens 30. Specifically,the light source 20 is located so as to be decentered with respect tothe central axis Ax1 of the condensing lens 30 in the vertical direction(the direction of Z-axis and −Z-axis). Of course, the light source 20may be located so as to be decentered with respect to the central axisAx1 of the condensing lens 30 in the horizontal direction (the directionof Y-axis and −Y-axis). Alternatively, the light source 20 may belocated so as to overlap the central axis Ax1 of the condensing lens 30when viewed in the vertical direction.

The light source 20 is spaced apart from the central axis Ax1 of thecondensing lens 30 in a first direction (a direction of Z-axis) which isperpendicular to the central axis Ax1 of the condensing lens 30.

The first light 21 generated from the light source 20 is incident on apoint that is decentered with respect to the central axis Ax1 of thecondensing lens 30, and is then incident on the first optical pathconversion member 40 through a front surface 31 of the condensing lens30.

The first optical path conversion member 40 is disposed on the frontsurface 31 of the condensing lens 30 for reflecting the first light 21having passed through the condensing lens 30 to provide first reflectedlight 22 to pass through the condensing lens 30.

Specifically, the first optical path conversion member 40 is arrangedsuch that the first reflected light 22 can pass through the condensinglens 30 from the front surface 31 to the rear surface 32 thereof. Morespecifically, the first optical path conversion member 40 is arrangedsuch that the first reflected light 22 is incident on the first regionof the front surface 31 of the condensing lens 30, and is then radiatedfrom the first region of the rear surface 32 of the condensing lens 30.

In addition, the first optical path conversion member 40 may include aplanar surface or a curved surface. In particular, a plurality of firstoptical path conversion members 40 may be arranged in a stair shape inresponse to the number of light sources 20. Furthermore, the firstoptical path conversion member 40 may be rotatable so as to adjust theangle of the first reflected light 22.

Meanwhile, a spot S formed as the result of the first reflected light 22being radiated from the rear surface 32 of the condensing lens 30 isspaced apart from the central axis Ax1 of the condensing lens 30 in thefirst direction. If the first optical path conversion member 40 isdisposed on the central axis Ax1 of the condensing lens 30, the distancebetween the first optical path conversion member 40 and the light sourceis increased, with the result that the overall length of the lightemitting module 10 is increased.

For this reason, the first optical path conversion member 40 is locatedso as to be decentered with respect to the central axis Ax1 of thecondensing lens 30 in the vertical direction (the direction of Z-axisand −Z-axis). Of course, the first optical path conversion member 40 maybe located so as to be decentered with respect to the central axis Ax1of the condensing lens 30 in the horizontal direction (the direction ofY-axis and −Y-axis). Alternatively, the first optical path conversionmember 40 may be located so as to overlap the central axis Ax1 of thecondensing lens 30 when viewed in the vertical direction. Specifically,the first optical path conversion member 40 and the condensing lens 30are arranged such that the first optical path conversion member 40 andthe condensing lens 30 at least partially overlap each other when viewedfrom the front of the condensing lens 30.

The first optical path conversion member 40 may be disposed at aposition spaced apart from the central axis Ax1 of the condensing lens30 in the first direction (the direction of Z-axis) which isperpendicular to the central axis Ax1 of the condensing lens 30.

The first optical path conversion member 40 is disposed on the frontsurface 31 of the condensing lens 30. Specifically, the first opticalpath conversion member 40 is disposed so as to contact the front surface31 of the condensing lens 30.

The first optical path conversion member 40 covers a portion of thefront surface 31 of the condensing lens 30. Specifically, the firstoptical path conversion member 40 covers a portion of the first regionof the front surface 31 of the condensing lens 30. The area of the firstoptical path conversion member 40 may be greater than the sectional areaof the first light 21 emitted from the light source 20. In addition, thearea of the first optical path conversion member 40 may be less than 10%the area of the front surface 31 of the condensing lens 30.

A light emitting module disclosed in a prior application that was filedby the applicant before filing of the present application is problematicin that the first optical path conversion member 40 is disposed in frontof the condensing lens 30 in a state in which the first optical pathconversion member 40 is spaced apart from the condensing lens 30,whereby the loss of light occurs when light radiated from the condensinglens 30 passes through the air. In addition, the light emitting moduledisclosed in the prior application has other problems in that astructure for fixing the first optical path conversion member 40 isneeded, and light is blocked by the structure for fixing the firstoptical path conversion member 40, whereby the loss of light occurs.

The light emitting module according to the present invention isconfigured such that the first optical path conversion member 40 isdisposed on the front surface 31 of the condensing lens 30. As a result,the light emitting module according to the present invention has anadvantage in that the size of the light emitting module is reduced. Inaddition, light radiated from the condensing lens 30 does not passthrough the air, whereby the loss of light is reduced. Furthermore, nostructure for fixing the first optical path conversion member 40 isneeded.

The first optical path conversion member 40 is disposed in contact withthe front surface 31 of the condensing lens 30. For example, the firstoptical path conversion member 40 may be coated on the front surface 31of the condensing lens 30, or may be inserted into a recess formed inthe front surface 31 of the condensing lens 30, which will be describedhereinafter.

For example, the first optical path conversion member 40 has areflection surface intersecting an arbitrary line that is parallel tothe optical axis. Here, the first optical path conversion member 40 maybe made of a material having a good reflection property, for example, amaterial selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir,Ru, Mg, Zn, Pt, Au, Hf, and a combination thereof.

The second optical path conversion member 50 is disposed behind thecondensing lens 30 for reflecting the first reflected light 22 toprovide second reflected light 23 to pass through the condensing lens30.

The first reflected light 22, which is incident on the front surface 31of the condensing lens 30 from the first optical path conversion member40, is refracted at the boundary surfaces of the condensing lens 30, andis radiated from the rear surface 32 of the first region of thecondensing lens 30. The first reflected light 22, having passed throughthe condensing lens 30, is incident on the second optical pathconversion member 50, and is reflected as the second reflected light 23from the second optical path conversion member 50. The second reflectedlight 23 is incident on the rear surface 32, which is aligned with thecentral axis Ax1 of the condensing lens 30. The second reflected light23, which is incident on the condensing lens 30, is refracted at theboundary surfaces of the condensing lens 30, and is radiated to thefront through the front surface 31 of the condensing lens 30.

Light emitted from the light source 20 is focused while sequentiallypassing through the upper half part of the condensing lens 30, the firstoptical path conversion member 40, the upper half part of the condensinglens 30, the second optical path conversion member 50, and the middlepart of the condensing lens 30. The upper half part of the condensinglens 30 is the upper region of the condensing lens 30 on the basis ofthe central axis Ax1 of the condensing lens 30. The upper half part ofthe condensing lens 30 is a first region of the condensing lens 30. Thelower half part of the condensing lens 30 is the lower region of thecondensing lens 30 on the basis of the central axis Ax1 of thecondensing lens 30. The lower half part of the condensing lens 30 is asecond region of the condensing lens 30. The middle part of thecondensing lens 30 is a predetermined region near the central axis Ax1of the condensing lens 30.

In one embodiment, the first optical path conversion member 40specularly reflects light for light focusing. The second optical pathconversion member 50 specularly reflects light.

The reflection surface of the second optical path conversion member 50is arranged so as to intersect an arbitrary line that is parallel to thecentral axis Ax1 of the condensing lens 30. Specifically, the secondoptical path conversion member 50 is arranged such that the secondreflected light 23, provided by the second optical path conversionmember 50, is aligned with the central axis Ax1 of the condensing lens30. That is, the second reflected light 23 passes through the centralaxis Ax1 of the condensing lens 30. In one embodiment, the secondoptical path conversion member 50 is disposed on the central axis Ax1 ofthe condensing lens 30. In another embodiment, however, the secondoptical path conversion member 50 may be located so as to be decenteredwith respect to the central axis Ax1 of the condensing lens 30.

The wavelength conversion unit 70 receives the second reflected light23, converts the wavelength of the received second reflected light 23,and radiates light the wavelength of which has been converted. Forexample, the wavelength conversion unit 70 may convert the wavelength ofblue-based light generated by the light source 20 into white-basedlight.

The wavelength conversion unit 70 may be formed of a well-knownphosphor, which converts the wavelength of light. The details of thewavelength conversion unit 70 will be described hereinafter.

After passing through the wavelength conversion unit 70, the secondreflected light 23 is incident on the condensing lens 30 and/or theauxiliary condensing lens 60. For example, as shown in FIG. 1, thewavelength conversion unit 70 is disposed between the condensing lens 30and the second optical path conversion member 50. The second reflectedlight 23, radiated from the second optical path conversion member 50, isincident on the middle part of the condensing lens 30 through thewavelength conversion unit 70.

Specifically, the wavelength conversion unit 70 is located on thecentral axis Ax1 of the condensing lens 30. The second reflected light23, radiated from the wavelength conversion unit 70, is radiated aheadof the optical axis Ax. That is, the second reflected light 23, radiatedfrom the wavelength conversion unit 70, becomes fan-shaped light whichis directed at a predetermined angle in upper and lower directions basedon the central axis Ax1 of the condensing lens 30. In other words, thelight, radiated from the wavelength conversion unit 70, is incidenttoward the condensing lens 30 at the rear of the condensing lens 30 andat a point on the central axis Ax1 of the condensing lens 30.

The second reflected light 23 is incident on the rear surface 32 of thecondensing lens 30, is refracted at the boundary surfaces of thecondensing lens 30, and is radiated from the condensing lens 30. Thesecond reflected light 23 having passed through the condensing lens 30has a smaller radiation angle than the second reflected light 23 that isincident on the condensing lens 30.

Accordingly, the second reflected light 23 having passed through thecondensing lens 30 is diffused while maintaining a certain degree ofstraightness. Such second reflected light 23 may be used as a low beamin a lamp device for vehicles, which illuminates a region spaced apartonly by a short distance.

In another embodiment, the second reflected light 23 may be convertedinto light that is approximately parallel to the optical axis so as tobe used as a high beam for illuminating a region spaced apart by a longdistance. In this case, the light emitting module according to thisembodiment may further include an auxiliary condensing lens 60 forconcentrating the second reflected light 23 having passed through thecondensing lens 30 on a predetermined spot in the front.

The auxiliary condensing lens 60 condenses light incident from the rearof the optical axis into a space in front of the optical axis.

The auxiliary condensing lens 60 refracts the incident light due to theshape of the auxiliary condensing lens 60 and the difference inrefractive index between the auxiliary condensing lens 60 and theoutside. The refractive index of the auxiliary condensing lens 60 may begreater than 1. For example, the refractive index of the auxiliarycondensing lens 60 may range from 1.5 to 1.6.

A central axis Ax2 of the auxiliary condensing lens 60 overlaps thecentral axis Ax1 of the condensing lens 30. Specifically, the auxiliarycondensing lens 60 is located so as to overlap the condensing lens 30when viewed from the front.

The central axis Ax2 of the auxiliary condensing lens 60 is located soas to be parallel to the central axis Ax1 of the condensing lens 30.

The light incident on the auxiliary condensing lens 60 from the rear isrefracted at the boundary surfaces of the auxiliary condensing lens 60,and is radiated parallel to the optical axis.

The light, whose wavelength is converted by and which is reflected fromthe second optical path conversion member 50, is incident on the rearsurface 32 of the condensing lens 30 in a state in which the lightspreads radially from the central axis of the condensing lens 30, and isthen radiated from the front surface 31 of the condensing lens 30. Atthis time, the radiation angle of the light radiated from the frontsurface 31 of the condensing lens 30 is smaller than the radiation angleof the light incident on the rear surface 32 of the condensing lens 30.The light radiated from the front surface 31 of the condensing lens 30is incident on the auxiliary condensing lens 60, which efficientlyconverts the light into light parallel to the optical axis. Theauxiliary condensing lens 60 may be made of the same material as thecondensing lens 30.

FIG. 11 is a reference view for explaining the position of the lightemitting module according to the embodiment of the present invention.

Using the above refraction formula, a distance h between each componentand the central axis Ax1 of the condensing lens 30 can be calculated.

The condensing lens 30 in this embodiment is embodied as an asphericallens, in which a radius of curvature of a center portion is smaller thanthat of an edge portion.

The light source 20, the first optical path conversion member 40, thesecond optical path conversion member 50, and the wavelength conversionunit 70 are disposed so as to overlap the condensing lens 30 when viewedfrom the front of the central axis Ax1 of the condensing lens 30.Therefore, the size of a housing accommodating the light emitting module10 may be reduced to the size of the condensing lens 30.

Specifically, a first distance h1 between the central axis Ax1 of thecondensing lens 30 and the light source 20 is smaller than a radius L ofthe condensing lens 30. Here, the first distance h1 is calculated usingthe above-mentioned distance calculation formula.

In addition, a second distance h2 between the central axis Ax1 of thecondensing lens 30 and the second optical path conversion member 50 is0. The second optical path conversion member 50 is located behind therear surface 32 of the condensing lens 30 such that the second opticalpath conversion member 50 is spaced apart from the condensing lens 30 inthe rearward direction.

Meanwhile, a third distance h3 between the central axis Ax1 of thecondensing lens 30 and the first optical path conversion member 40 issmaller than the radius L of the condensing lens 30, and is greater than0. Of course, the third distance h3 is also calculated using theabove-mentioned distance calculation formula. For example, a ratio ofthe first distance h1 to the third distance h3 may be in the range of1:0.9 to 1:1.1. Specifically, the first distance hl and the thirddistance h3 may be equal to each other.

A sixth distance h6 between the central axis Ax1 of the condensing lens30 and an exit spot S of the first reflected light 22 may be smallerthan the first distance h1 or the second distance h2. For example, aratio of the first distance h1 of the light source 20 to sixth distanceh6 of the exit spot S may be in the range of 1:0.1 to 1:0.6.

For convenience of assembly, the light emitting module 10 is generallyaccommodated in a hexahedron-shaped housing. By disposing the lightsource 20 at the upper portion behind the condensing lens 30 anddisposing the second optical path conversion member 50 at the middleportion behind the condensing lens 30, the length of the light emittingmodule 10 may be reduced, and space utilization may be maximized. As aresult, the light emitting module 10 may be easily accommodated in thehousing.

Furthermore, by disposing the auxiliary condensing lens 60 in front ofthe condensing lens 30 and disposing the first optical path conversionmember 40 at the upper portion in front of the condensing lens 30, thelength of the light emitting module 10 may be reduced, and spaceutilization may be maximized. As a result, the light emitting module 10may be easily accommodated in the housing.

In addition, by disposing the second optical path conversion member 50and the wavelength conversion unit 70 on the central axis Ax1 of thecondensing lens 30, light is incident on the condensing lens 30 from thewavelength conversion unit 70 along the central axis Ax1 of thecondensing lens 30, whereby light efficiency is improved.

FIG. 15A is a conceptual view of a light emitting module according toanother embodiment of the present invention.

Referring to FIG. 15A, a light emitting module 10 according to thisembodiment is different from the light emitting module shown in FIG. 9in terms of the disposition of the second optical path conversion member50. Other components of the light emitting module 10 according to thisembodiment are identical to those of the light emitting module shown inFIG. 9. Hereinafter, therefore, only the difference between the lightemitting module 10 according to this embodiment and the light emittingmodule shown in FIG. 9 will be described.

In this embodiment, the second optical path conversion member 50 isdecentered with respect to the central axis Ax1 of the condensing lens30. Specifically, the second optical path conversion member 50 is spacedapart from the central axis Ax1 of the condensing lens 30 in the firstdirection (the direction of Z-axis). In this case, the reflectionsurface of the second optical path conversion member 50 is disposed soas to be perpendicular to an arbitrary line that is parallel to thecentral axis Ax1 of the condensing lens 30.

Second reflected light 23 radiated from the second optical pathconversion member 50 is incident on the wavelength conversion unit 70.In this embodiment, overlapping between the light incident on the secondoptical path conversion member 50 and the light radiated from thewavelength conversion unit 70 may be reduced.

FIG. 15B is a conceptual view of a light emitting module according toanother embodiment of the present invention.

Referring to FIG. 15B, a light emitting module 10 according to thisembodiment is different from the light emitting module shown in FIG. 9in terms of the disposition of the wavelength conversion unit 70.

In this embodiment, the wavelength conversion unit 70 is disposed on onesurface of the condensing lens 30. Specifically, the wavelengthconversion unit 70 is disposed on the rear surface 32 of the condensinglens 30. The wavelength conversion unit 70 may be attached to or coatedon the rear surface 32 of the condensing lens 30.

In this case, the wavelength conversion unit 70 is located at the centerof the rear surface 32 of the condensing lens 30.

FIG. 15C is a conceptual view of a light emitting module according toanother embodiment of the present invention.

Referring to FIG. 15C, a light emitting module 10 according to thisembodiment is different from the light emitting module shown in FIG. 9in terms of the disposition of the wavelength conversion unit 70.

In this embodiment, the wavelength conversion unit 70 is disposed on onesurface of the condensing lens 30. Specifically, the wavelengthconversion unit 70 is disposed on the front surface 31 of the condensinglens 30. The wavelength conversion unit 70 may be attached to or coatedon the front surface 31 of the condensing lens 30. The wavelengthconversion unit 70 is located at the center of the front surface 31 ofthe condensing lens 30.

In this case, second reflected light 23 radiated from the second opticalpath conversion member 50 is condensed while passing through the centerof the condensing lens 30, and is provided to the wavelength conversionunit 70, which is disposed on the front surface 31 of the condensinglens 30. The wavelength of the light is converted by the wavelengthconversion unit 70. The light the wavelength of which has been convertedis provided to the auxiliary condensing lens 60.

FIG. 15D is a conceptual view of a light emitting module according to afurther embodiment of the present invention.

Referring to FIG. 15C, a light emitting module 10 according to thisembodiment is different from the light emitting module shown in FIG. 9in terms of the disposition of the wavelength conversion unit 70.

In this embodiment, the wavelength conversion unit 70 is disposedbetween the condensing lens 30 and the auxiliary condensing lens 60.Specifically, the wavelength conversion unit 70 is located on thecentral axis Ax1 of the condensing lens 30 between the condensing lens30 and the auxiliary condensing lens 60.

In this case, second reflected light 23 radiated from the second opticalpath conversion member 50 is condensed while passing through the centerof the condensing lens 30, and is provided to the wavelength conversionunit 70, which is disposed in front of the condensing lens 30. Thewavelength of the light is converted by the wavelength conversion unit70. The light the wavelength of which has been converted is provided tothe auxiliary condensing lens 60.

FIG. 16 is a view illustrating an optical path of the light emittingmodule according to the present invention.

Referring to FIG. 16, first light 21 generated by the light source 20 isincident on the upper region (first region) of the condensing lens 30,is refracted, and is then radiated from the condensing lens 30. Thefirst light 21 radiated from the condensing lens 30 is incident on thefirst optical path conversion member 40.

The first light 21 incident on the first optical path conversion member40 is reflected therefrom, and is radiated as first reflected light 22.The first reflected light 22 is incident on the upper region (secondregion) of the condensing lens 30. The first reflected light 22 isradiated rearward through the upper region of the condensing lens 30.

The first reflected light 22 radiated from the condensing lens 30 isincident on the second optical path conversion member 50. The firstreflected light 22 is converted into white light by wavelengthconversion of the second optical path conversion member 50, is reflectedfrom the second optical path conversion member 50, and is radiated assecond reflected light 23.

At this time, since the second reflected light 23 undergoes Lambertianreflection, the second reflected light 23 becomes fan-shaped light whichis directed at a predetermined emission angle based on an arbitrary lineparallel to the optical axis.

The second reflected light 23 is incident on the middle part of thecondensing lens 30, is refracted, and is radiated ahead of thecondensing lens 30.

The second reflected light 23 radiated from the condensing lens 30 iscondensed by the auxiliary condensing lens 60, and is radiated as secondlight 24.

In particular, the majority of the second reflected light 23 is incidentinto the auxiliary condensing lens 60, and is refracted so as to becomeparallel light.

FIG. 17 is a view illustrating a car equipped with the light-emittingmodule 10 according to the present invention, and FIG. 18 is a sectionalview illustrating a lamp device for vehicles including thelight-emitting module 10 according to the present invention.

Referring to FIG. 17, the light-emitting module 10 according to theembodiment is mounted to the front portion of a vehicle 1. Thelight-emitting module 10 may be accommodated in an automotive lampdevice 100, and the automotive lamp device 100 may be mounted to thefront portion of the vehicle 1. In this embodiment, the automotive lampdevice 100 includes a head lamp for illuminating the area ahead whiledriving at night, a fog lamp, a turn signal lamp and so on.

In another embodiment, the automotive lamp device may be mounted to therear portion of the vehicle 1 so as to function as a tail lamp.

Referring to FIG. 18, the automotive lamp device 100 according to anembodiment of the present invention comprises the lamp housing 110 andthe light-emitting module 10 accommodated in the lamp housing 110.

According to embodiments, the automotive lamp device 100 may furthercomprise a light source unit 400.

The lamp housing 110 provides a space in which the light-emitting module10 and/or the light source unit 400 are disposed.

The light source unit 400 functions to output light which is necessaryfor vehicle driving.

Here, the light-emitting module 10 and the light source unit 400 mayemit the same type of light. Preferably, the light emitted from thelight-emitting module 10 may have a different color from that emittedfrom the light source unit 400, or one thereof may be plane light andthe other may be point light.

The light emitted from the light source unit 400 has good diffusivityand may be used to illuminate a region spaced apart by a short distance.The light emitted from the light-emitting module 10 has goodstraightness and may be used to illuminate a small region spaced apartby a long distance.

The light-emitting module 10 may use a laser diode, and the light sourceunit 400 may use a xenon lamp.

According to embodiments, by disposing the light source at the upperportion behind the condensing lens and disposing the second reflectionunit at the lower portion behind the condensing lens, the length of thelight-emitting module may be reduced, and space utilization may bemaximized. As a result, the light-emitting module may be easilyaccommodated in the housing.

Further, by disposing the auxiliary condensing lens at the lower portionin front of the condensing lens and disposing the first reflection unitat the upper portion in front of the condensing lens, the length of thelight-emitting module may be reduced, and space utilization may bemaximized, so that the light-emitting module can be easily accommodatedin the housing.

Further, since the condensing lens is divided into the upper and lowerregions, each of which is used as an optical path, the number ofcomponents may be decreased and the manufacturing cost may be reduced.

Further, by using the reflective phosphor, the optical efficiency may beenhanced.

Further, the light-emitting module may emit light having good lightconvergence and straightness, despite having a simple structure.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. (canceled)
 2. A light emitting module comprising: a lens; a lightsource configured to provide first light to pass through the lens; afirst reflection unit configured to reflect the first light to providefirst reflected light to pass through the lens; a second reflection unitconfigured to reflect the first reflected light to provide secondreflected light to pass through the lens; and a phosphor configured toreceive the second reflected light, convert a wavelength of the receivedsecond reflected light, and radiate light the wavelength of which hasbeen converted.
 3. The light emitting module according to claim 2,wherein the phosphor is disposed between the second reflection unit andthe lens.
 4. The light emitting module according to claim 2, furthercomprising an auxiliary lens for condensing the second reflected light.5. The light emitting module according to claim 4, wherein the phosphoris disposed between the lens and the auxiliary lens.
 6. The lightemitting module according to claim 2, wherein the phosphor is positionedon one surface of the lens.
 7. The light emitting module according toclaim 2, wherein the phosphor comprises: an incidence surface on whichthe second reflected light is incident; an emission surface from whichthe incident second reflected light is emitted; and side surfaces thatconnect the incidence surface and the radiation surface.
 8. The lightemitting module according to claim 7, further comprising a heat sinkdisposed on the side surfaces of the phosphor in a contact fashion. 9.The light emitting module according to claim 7, wherein the incidencesurface and the emission surface of the phosphor are arranged so as tointersect a central axis of the lens.
 10. The light emitting moduleaccording to claim 2, wherein the light source and the first reflectionunit are positioned so as to be decentered with respect to a centralaxis of the lens.
 11. The light emitting module according to claim 10,wherein the second reflection unit is positioned so as to be decenteredwith respect to the central axis of the lens.
 12. The light emittingmodule according to claim 11, wherein the light source and the secondreflection unit are arranged so as to be opposite to each other withrespect to the central axis of the lens.
 13. The light emitting moduleaccording to claim 4, wherein the auxiliary lens is positioned so as tobe decentered with respect to a central axis of the lens.
 14. The lightemitting module according to claim 4, wherein the auxiliary lens isconfigured such that a central axis of the auxiliary lens is alignedwith a central axis of the lens.
 15. The light emitting module accordingto claim 3, wherein the phosphor is positioned on a central axis of thelens.
 16. The light emitting module according to claim 3, wherein thephosphor is positioned so as to be decentered with respect to a centralaxis of the lens.
 17. The light emitting module according to claim 2,wherein the lens is divided into a first region and a second region by asection cut along a central axis of the lens, and wherein the firstlight is incident on the first region, the first reflected light isincident on the second region, and the second reflected light isincident on the second region.
 18. The light emitting module accordingto claim 17, wherein the first light is incident parallel to the centralaxis of the lens.
 19. The light emitting module according to claim 2,wherein the second reflected light emitted from the second reflectionunit passes through a central axis of the lens.
 20. The light emittingmodule according to claim 2, wherein the first reflection unit isdisposed on a front surface of the lens.
 21. The light emitting moduleaccording to claim 20, wherein the first reflection unit comprises aplurality of dielectric layers having different refractive indices.